 /*******************************************************************************
  * Copyright (c) 2000, 2005 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM - Initial API and implementation
  *******************************************************************************/
 package org.eclipse.core.internal.resources;

 import java.io.DataInputStream ;
 import org.eclipse.core.internal.utils.Messages;
 import org.eclipse.core.internal.watson.ElementTree;
 import org.eclipse.core.resources.IProject;
 import org.eclipse.core.resources.IResourceStatus;
 import org.eclipse.core.runtime.CoreException;
 import org.eclipse.core.runtime.IProgressMonitor;
 import org.eclipse.osgi.util.NLS;

 /**
  * Default tree reader that does not read anything. This is used in cases
  * where the tree format is unknown (for example when opening a workspace
  * from a future version).
  */
 public abstract class WorkspaceTreeReader {
     /**
      * Returns the tree reader associated with the given tree version number
      */
     public static WorkspaceTreeReader getReader(Workspace workspace, int version) throws CoreException {
         switch (version) {
             case ICoreConstants.WORKSPACE_TREE_VERSION_1 :
                 return new WorkspaceTreeReader_1(workspace);
             case ICoreConstants.WORKSPACE_TREE_VERSION_2 :
                 return new WorkspaceTreeReader_2(workspace);
             default :
                 // Unknown tree version - fail to read the tree
 String msg = NLS.bind(Messages.resources_format, new Integer (version));
                 throw new ResourceException(IResourceStatus.FAILED_READ_METADATA, null, msg, null);
         }
     }

     /**
      * Returns a snapshot from the stream. This default implementation does nothing.
      */
     public abstract ElementTree readSnapshotTree(DataInputStream input, ElementTree complete, IProgressMonitor monitor) throws CoreException;

     /**
      * Reads all workspace trees from the stream. This default implementation does nothing.
      */
     public abstract void readTree(DataInputStream input, IProgressMonitor monitor) throws CoreException;

     /**
      * Reads a project's trees from the stream. This default implementation does nothing.
      */
     public abstract void readTree(IProject project, DataInputStream input, IProgressMonitor monitor) throws CoreException;
 }

